1. Field of Invention
The invention relates to a mattress system with an upper mattress and a lower mattress.
2. Description of Related Art
With the most widely known constructions on the market, the lower mattress comprises connecting carrier elements in the shape of laterally running boards on top of which the upper mattress lies with a typically rectangular frame. That has the disadvantage that the boards are either very stiff and have practically no spring effect, which can be only partially balanced out by flexible suspension of the same; or in case they are flexible, an unbalanced spring effect is considerably stronger in the middle than at the edge. In the latter case, the boards sag because of a larger stress in the middle in an undesired dimension, especially with wide beds. Constructions are indeed known that achieve an improvement of the simple board construction (CH-PS 506 275, CH-PS 483 234, CH-PS 474 982) by inserting intermediate supports and other construction elements. Still, they cannot remove an intrinsic weakness of the lower mattress' boards, despite the partly substantial constructive effort, namely that the spring characteristic is specifically variable only in the longitudinal direction up to a certain degree and is, thus, adjustable to the different frame stress. Similar is the problem with the upper mattresses, where the conventional spring cores with helical springs essentially show the same spring characteristics.